As an important broadband antenna, the double-ridged horn antenna is widely used in electromagnetic compatibility testing. In this paper, a 0.2 ~ 2 GHz double-ridged horn antenna is designed by software simulation. The dimensions of each part of the antenna are optimized by simulation calculation, and the parameters such as standing wave ratio, gain and pattern of the antenna are calculated. The parameters of the antenna are measured, and the measured results are basically consistent with the simulation results.